Time-keeping apparatus

ABSTRACT

The time-keeping apparatus comprises a timer unit capable of emitting time signals and an indicating unit having timeindicator such as hour and minute hands. The timer unit emits a time signal wave such as a supersonic wave at constant intervals by means of a synchronous motor serving as the reference of time. Communication between the timer unit and the time-indicating unit is effected by a wireless system. A signal receiver incorporated in the time-indicating unit is rendered to the condition of being able to receive a time signal a little before this signal wave is emitted to function so that, upon receipt of same, it drives a time-indicator actuating mechanism. Thereafter, the receiver is relieved of this condition. The time-indicator actuating mechanism thus driven causes the hands to be displaced in their positions in accurate agreement with the advancement of time.

United States Patent [1 1 Kikuchi July 31, 1973 TIME-KEEPING APPARATUS Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons Jackmon 75 I t T m K k h Tokoroza a-sh men or w Attorney-Cushrnan, Darby & Cushman [73] Assignee: Kabushiki Kaisha Koparu,

Tokyo-to, Japan [57] ABSTRACT [22] Fihdz Man 16 1971 The time-keeping apparatus comprises a timer unit capable of emittm time signals and an indicatin unit 8 8 PP N 124,759 having time-indicator such as hour and minute hands.

The timer unit emits a time signal wave such as a super- Foreign Application Priority Data sonic wave at constant intervals by means of a synchro- Mar 27 l 970 13 an /2572, nous motor serving as the reference of time. Communip cation between the timer unit and the time-indicating unit is effected by a wireless system. A signal receiver g 58/26 n, incorporated in the time-indicating unit is rendered to 58] Field R 2446 the condition of being able to receive a time signal a lit- 58/34 35 3 5 tle before this signal wave is emitted to function so that, upon receipt of same, it drives a time-indicator actuata ing mechanism. Thereafter, the receiver is relieved of [56] References cued this condition. The time-indicator actuating mecha- UNlTED STATES PATENTS nism thus driven causes the hands to be displaced in 3, 2 ,3 3 g l i R their positions in accurate agreement with the advance ,4 l, 1 6/19 e ter ine, r. et a R m f time 3,520,128 7/1970 Novikov et al 58/35 R X 1 Claim, 3 Drawing Figures ON TIMER CKT RECEIVER PAIENIEU M3! FIG.

As Q1 1 RECEIVER ON TIMER CKT LOFF TIMER CKT FIG.3

- RECEIVER INVENTOR. JM

BY MW 1 HTTaen/E l5 TIME-KEEPING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is concerned with a cordless time-keeping apparatus comprising two separate sections, i.e., a timer unit and a time-indicating unit, wherein said timer unit is controlled with the frequency of the AC power source provided in general households, and arranged so that the communication between the timer unit and the time-indicating unit is effected by means of signal waves, whereby accurate time indication is attained.

2. Description of the Prior Art Time-keeping apparatuses or timepieces which are controlled by frequency are being widely used. However, these conventional time-keeping apparatuses are such that their timer unit is arranged integrally with the time-indicating unit. Accordingly, the time-keeping apparatus of the prior art is connected to the power source by means of an electric'cord. This fact has given rise to the inconveniences that the place for installing the timepiece is limited and that one apts to trip over the cord, leading to an accident of some kind or other.

To eliminate such inconveniences, there has been proposed a cordless timepiece having dry batteries housed therein to drive a timer unit. However, a cordless timepiece of this prior type has been found difficult to attain accurate time control as compared with the conventional arrangement described above which utilizes an AC power source. For this reason, the errors accumulated during the continuous time-keeping ac tion have tended to provide inaccurate indication of time. Also, an attempt'of preventing this inaccuracy in time indication by the provision of a high precision apparatus naturally resulted in a substantial hike in cost of manufacture and accordingly ended in the provision of an expensive timepiece.

' SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a cordless time-keeping apparatus comprising a timer unit which utilizes the frequency of the AC power source for general households to cause the timer unit to emit signal waves, said timer unit being arranged so that it gives out a signal wave such as a supersonic wave at constant intervals of time, and a timeindicating unit provided separately from said timer unit, said time-indicating unit comprising means for receiving said signal wave and a mechanism interlocked with said receiver to enable same to actuate the timeindicator, whereby said time-indicating unit can be separated from the AC power source of the household without being connected thereto by a cord to make the timepiece a cordless one.

Another object of the present invention is to provide a time-keeping apparatus wherein its time-indicating unit is such that the period of time at which it can receive a signal from the timer unit is limited so that this time-indicating unit is rendered incapable of receiving any signal wave during any other periods that limited period, thereby eliminating its erroneous behavior due to the effects of external noise components, whereby the period for emittance of a signal wave by the timer unit is always kept synchronous with the period of driving the timer-indicator actuating mechanism provided at constant time intervals by utilizing a switch which is,

in the time-indicating unit to thereby insure accurate time-keeping operation.

Still another object of the present invention is to provide a time-keeping apparatus arranged so that the period of time allowed for receiving a certain one of a series of signal waves emitted at constant intervals of time is determined by starting computation from the time of arrival of the immediately preceding signal wave relative to said certain one signal wave, so that even after the lapse of a substantial length of time, there can be maintained such a signal wave-receiving condition as is always synchronous with the time at which the signal wave is emitted from the timerunit.

The timer unit of the time-keeping apparatus according to the present invention is arranged so that a signal wave such as a supersonic wave is radiated into space controlled by a synchronous motor. In this instance, said synchronous motor is rotated at such a rate as is always synchronous with the precision frequency regulated at the power generating plant. Accordingly, the preciseness of time expected of this time pieceis identical with the precisenessof the frequencyof the AC power source at the power generating plant. A novel feature of the present invention that should be stressed in particular lies in the fact that the time-indicating unit which is intended to expressly indicate the correct progressing lapse of time and which constitutes one of the two component units of the apparatus has batteries housed therein so that this unit can be installed freely at any desired place separately from the aforesaid timer unit which constitutes theother of the two component units of the apparatus.

" These and other objects, features as well as the attendant advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings which show one example as well as another modified example of the apparatus of the present invention. A

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic explanatory representation showing an example of the timer unit which is connected to the power source of a household;

FIG. 2 is a block-style explanatory representation showing an example of the time-indicating unit used in the time-keeping apparatus of the present invention, which is installed separately from the timer unit shown in FIG. I; and

FIG. 3 is a somewhat diagrammatic representation of an electric circuitry according to the present invention, which at sight is of a close resemblance with that of the time-indicating unit shown in FIG. 2 but which actually is locally modified relative thereto and is shown in a greater detail.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, there is shown a timer unit A. In this timer unit A, reference symbol Al represents a plug which is connected to a household power source. Symbol A2 represents a casing for housing a synchronous motor (not shown) which is controlled with the frequency of the power source and for housing a cam plate A3 having a cam A311 and being rotated by said motor at the rate of l revolution per minute. A4 represents a signal emitter for radiating a supersonic wave of the order of several tens of KHz which is in excess of the audible range. A represents a switch for actuating the signal emitter A4 whenever it is closed by the cam A3a of the cam plate A3.

In FIG. 1, the timer unit A starts it action upon its plug Al is connected to the household AC power source. whereupon, the synchronous motor is rotated first, causing the cam plate A3 to rotate clockwise. Accordingly, the cam plate A3 effects 1 revolution with the cycle of 1 minute. Arrangement is provided so that during this one cycle, the rotation of this cam plate causes the switch A5 to be closed for 5 seconds by the cam A3a, and that for the remainder of the time of I minute other than said 5 seconds, this switch A5 is held open. Throughout said length of time in which the switch A5 is kept closed, the signal emitter A4 is actuated continuously to emit a supersonic wave of the order of several tens of KHz which is in excess of the audible range and is of no substantially great directivity.

In FIG. 2, on the other hand, there is shown a timeindicating timer unit B. In the drawing showing this time-indicating unit, the reference symbol Bl represents a power source consisting of batteries. B2 represents an on-timer circuit, and B3 represents a receiver of a supersonic wave signal. B4 represents a plunger having a pawl 84a for feeding a ratchet wheel B5 which, in turn, is interlocked with a minute indicating board. B6 represents a first off-timer circuit for delaying its output for a certain length of time and for resetting the on-timer circuit B2 with this delay. B7 represents a switching transistor.

In FIG. 2, the timer-indicating unit B functions in such a way that its signal receiver B3 receives the supersonic wave emitted from the timer unit A to thereupon drive the plunger B4 so that its pawl B4a actuates the ratchet wheel B5 by one pitch to thereby advance the indication of time by 1 minute. During this part of operation, after the lapse of a length of time sufficient for the plunger to complete said advancement of time indication, the on-timer circuit B2 is re-set by the first off-timer circuit B6 of the feedback circuit provided with a time constant. whereupon, the on-timer circuit B2 drops the amount of current flowing toward the signal receiver B3 to a level lower than the breaking current of the transistor. This condition continues for 55 to 59 seconds to maintain the signal receiver B3 in its inoperative state. Thereafter, the on-timer circuit B2 again renders the transistor 7 conductive so that the receiver B3 is rendered to the signal-receiving condition. Thereafter, the aforesaid timer unit A emits a supersonic wave, and with this the above-described sequential actions are started over again.

In FIGS. 1 and 2, there has been shown an embodiment wherein the timer unit A is communicated with the timer-indicating unit B by a supersonic wave. It should be understood, however, that this communication may be effected by some other means such as wireless signaling means utilizing a signal wave consisting of an electric wave or a light wave, for example. However, if various factors, such as the manufacturing costs of both the signal emitter and the signal receiver, the effects to and from other instruments, and the distance to be covered by the wave, are taken into account, it may be said that the system utilizing a supersonic wave is most advantageous at the present stage of techniques. This holds true with another embodiment shown in FIG. 3 which will be described later.

In FIG. 3, there is shown a more concrete electric circuit of only the time-indicating unit B incorporating a partial modification of the embodiment shown in FIG. 2. It should be noted that the timer unit is omitted in FIG. 3. However, it is to be understood that the already discussed timer unit A shown in FIG. 1 is utilized in this embodiment.

As stated above, there is shown in FIG. 3 an entire view of another example of the time-indicating unit. In this drawing, reference numeral 1 represents a signal receiving device for receiving a supersonic signal wave emitted from the aforesaid timer unit A, and it comprises a signal receiver 2 having a microphone means (in case the receiver is one for receiving an electric wave, this microphone is substituted by an antenna) 20. Numeral 3 represents a time-indicator actuating mechanism which consists of a plunger comprising a solenoid 4 connected to the output terminal of the signal receiver 2, a movable iron core 5 having a pawl Slime. and a stop lever 5b both of which are integrally formed with said core, and a spring 6 for restoring the normal position of said iron core 5, and a ratchet wheel 7 which is coupled to the minute" indicating section which, in turn, is rotated at the end of every 1 minute as it is driven by the pawl 5a of the movable iron core 5. Numeral 8 represents a second off-timer circuit for rendering said signal receiving device 1 to the nonreceiving state for a predetermined length of timer. This second off-timer circuit comprises a time constant circuit consisting of a resistor 9 and a capacitor 10, a field effect transistor 11 whose gate electrode is connected to the juncture of the resistor 9 and the capacitor l0 and whose source potential is provided by a potentiometer l2, and a switch 13 for discharging the charge of the capacitor 10. It should be understood that the fixed contact 13a of the switch 13 intrudes in the path of movement of the stop lever 5b and serves as the stopper for restricting the amount of the downward movement of the movable iron core 5. On the other hand, the movable contact 13b normally is urged toward its open position and besides it is brought into contact with the fixed contact 13a in accordance with the contacting of the stop lever 5b with this fixed contact 13a. Numerals l4 and 15 represent transistors for connecting said signal receiving device 1 to the second off-timer circuit 8. Numeral 16 represents a power source consisting of batteries.

Now, the function of the time-indicating unit shown in FIG. 3 will be described. Whenever the switch 13 of the second off-timer circuit 8 is opened, there is effected the charging of the capacitor 10 via the resistor 9. When the potential of the thus charged gate of the field effect transistor 11 is in excess of the source potential, this transistor 11 is rendered conductive. whereupon, the transistors 14 and 15 are accordingly rendered conductive, so that the signal receiver 2 is rendered to the signal-receiving state. Now, let us assume that a signal wave is radiated continuously for several seconds during every minute from the signal emitter A4 of the timer unit A shown in FIG. 1. Whereupon, the signal receiving device 1 receives the signal wave through its microphone means 2a, and with this, the receiver 2 becomes actuated to supply a current to the solenoid 4 of the plunger. As a consequence, the movable iron core 5 of the plunger acts in such a way that its stop lever 5b urges the movable contact 13b to move from its intermediate position against the tension of the spring 6 which is intended for restoring the normal position of the movable iron core 5 to displace the movable contact l3b downwardly so as to cause it to contact the fixed contact 13a. On the other hand, the pawl 5a is brought into mesh with a tooth 7a of the ratchet wheel 7. When the switch 13 is thus closed, the accumulated charge of the capacitor 10 is caused to be discharged. As a consequence, the gate potential of the field effect transistor 11 drops to a level lower than the source potential. whereupon, the transistor 11 is rendered of and, accordingly, the transistors l4 and are also rendered off. As a consequence, the signal receiver 2 is rendered to the nonreceiving state, and the current to the solenoid 4 is cut off. As a result, the movable iron core 5 is returned upwardly by the tension of the spring 6. During the course of this upward movement of the iron core 5, the ratchet wheel 7 is rotated through a predetermined angle by the pawl 50 of said iron core 5, whereby the timeindicator is fed by 1 minute. On the other hand, this returning movement of the movable iron core 5 causes the switch 13 to be opened. Along with this, the capacitor 10 is again charged via the resistor 9. Let us now assume that the time constant for the length of time from the time that the potential of the thus charged capacitor 10 becomes in excess of the source potential of the field effect transistor 11 till the time at which this field effect transistor 11, and accordingly, the transistors 14 and 15 also, are rendered on in sequence, is set to approximately 1 minute. It should be understood that, during this length of time, the signal receiving device 1 is retained in its non-receiving state. Thereafter, when the respective transistors 11, 14 and 15 are rendered on in substantial synchronism with the time at which a signal wave is radiated from the timer unit, and when, accordingly, the signal receiving device 1 is again rendered to the signal receiving state, the aforesaid series of actions are started over again.

Explanation has been made by assuming that the signal wave is emitted at the rate of once per minute from the timer unit. It should be understood, however, that in case the signal wave is to be emitted N times per minute so that the usual alteration of time-indication effected only at the end of each minute is substituted by a series of stepwise indications of N times during 1 minute which is divided into N steps, the time constant which is determined by the aforesaid resistor 9 and the capacitor 10 is set to a length of time slightly smaller than l/N of a minute. For example, if the arrangement is such that a signal wave is emitted at the end of every 30 seconds from the timer unit and that, accordingly, the alteration of time indication for each minute is controlled by two intermittent actions during 1 minute of the indicator-actuating mechanism in the timeindicating unit, the time constant of the second offtimer circuit is set at a value slightly smaller than onehalf of a minute. It should be understood also that the aforesaid plunger may be substituted by other electro-' magnetic devices such as electromagnet or relay. it should be understood further that the method of indication to be employed by the time-keeping apparatus of the present invention may be either analog type or digital type. i

The apparatus according to the present invention has been discussed by referring to specific embodiments. it is to be understood that various modifications of the apparatus may be made in the design as well as the arrangement by those skilled in the art without departing the scope of the present invention which is defined by the appending claims.

I claim:

1. A time-keeping apparatus comprising: a time unit including;

a synchronous motor the rotation of which is controlled by an AC power source;

a signal-emitting device responsive to said motor for producing a signal wave at substantially constant intervals of time in accordance with said motor rotation;

and a time-indicating unit powered by a DC supply responsive to the signal wave for controlling the time-indication, said time-indicating unit including;

a signal receiving device activated in response to the signal wave;

an electromagnetic means coupled to the output of the signal receiving device including;

a solenoid, a moveable member adapted to be displaced from a normal position upon energization of the solenoid and a spring member for causing said moveable member to resume its normal position when de-energized,

a time-indicator actuating section responsive to the electromagnetic means being adapted to rotate through a predetermined angle as a result of the return movement of the moveable member, engaging therewith, upon returning to its normal position;

an off-timer circuit including a switch controlled by the electromagnetic means, for rendering said signal receiving device unresponsive to said timer unit for the period of time until the next signal wave; said switch including a set of contacts coupled to the signal receiving device for interrupting same upon actuation thereof when the moveable member is displaced, one of said contacts serving as a limit to the displacement of said moveable member.

r-rite 

1. A time-keeping apparatus comprising: a time unit including; a synchronous motor the rotation of which is controlled by an AC power source; a signal-emitting device responsive to said motor for producing a signal wave at substantially constant intervals of time in accordance with said motor rotation; and a time-indicating unit powered by a DC supply responsive to the signal wave for controlling the time-indication, said timeindicating unit including; a signal receiving device activated in response to the signal wave; an electromagnetic means coupled to the output of the signal receiving device including; a solenoid, a moveable member adapted to be displaced from a normal position upon energIzation of the solenoid and a spring member for causing said moveable member to resume its normal position when de-energized, a time-indicator actuating section responsive to the electromagnetic means being adapted to rotate through a predetermined angle as a result of the return movement of the moveable member, engaging therewith, upon returning to its normal position; an off-timer circuit including a switch controlled by the electromagnetic means, for rendering said signal receiving device unresponsive to said timer unit for the period of time until the next signal wave; said switch including a set of contacts coupled to the signal receiving device for interrupting same upon actuation thereof when the moveable member is displaced, one of said contacts serving as a limit to the displacement of said moveable member. 